Macbook does not reconize external hard drive

I have a 1 tier a byte Fantom Greendrive that my Macbook reconized the first couple of times I powered it on. I ejected it each time I was done but the last time I did this it continued to say to eject it. I did but it contiuned to ask so I just disconnected it. Now it will not see it no matter how many times I try. I have restarted the laptop, I have changed cables and now have it plugged into a usb hub. I cant format it bc it has hundreds of photos on it. I need help!